Speech aids for use by persons who have had laryngectomies electrically produce mechanical vibrations which are applied externally, passed through the soft tissues of the neck into the area of the mouth and throat and modulated by means of tongue and throat movements into comprehensible speech. Speech aids of this type, in most cases, have the shape of torch-shaped flashlights to be held in the hand by their shaft-like handles and pressed against the neck at their, flared ends, which contain the electromechanical vibration transducers. Rechargeable batteries are in most cases used as a source of power.
A drawback of such speech aids has been either that very large batteries have to be used, making long-term use of the device tiring, or that the batteries must be frequently recharged so, that a spare device must be available.
In addition, if speech which is suitably articulated for ready comprehension is to be produced, the fluctuations in loudness and intonation of normal voice production must be matched. These fluctuations vary widely, so that a large number of loudness and tone parameters must be produced. At least some of this has had to be carried out manually by the user.
This makes learning how to handle the speech aid more difficult and also increases its size and heaviness as a result of the multiplicity of components required.